1. Field of the Invention
The present invention relates to dilators or dilator assemblies for compressing fatty substances deposited in or on the walls and lumen of major arteries.
2. Description of the Prior Art
In our society and in other developed societies, the aging process is accompanied by the deposition of fatty substances in the walls and lumen of the major arteries. The precise causes of this buildup are unknown but are in all likelihood related to diet. The fatty substances are not deposited uniformly throughout the arterial system but, for reasons that are not well understood, are concentrated at various sites within the arteries. These deposits may take the form of hard crystalline masses within the wall of the artery, soft gelatinous masses within the lumen, or various combinations of these conditions. In some instances, these deposits build to such an extent that they severely restrict blood flow to body sites such as the lower extremeties, the brain and the heart.
In cases wherein the deposits have restricted blood flow to such an extent that the individual develops clinical symptoms which indicate that the normal course of life is threatened, the sections of artery which are obstructed by the deposits are removed and replaced with artificial arterial segments or the sections are bypassed using vein segments taken from another site in the body. In either case, the procedure requires a traumatic invasion of the individual's body which is both costly and of high risk.
It has recently been shown by Grunzig that an inelastic sack inserted into the blocked artery can, when properly positioned, be inflated and compress the deposit in the artery. Upon removal of the sack, the deposit remains compressed and the blood flow in the artery is substantially increased.
Since the sack is inserted into the arterial system through a simple incision, for instance, in the groin to reach the femoral artery, the surgical trauma is greatly reduced. Likewise, the risk of the procedure, although still significant, is greatly reduced.
Current methods of fabrication of sacks consist of the joining of a cylindrically shaped sack to the end of a tube which serves as an insertion guide and additionally for transfer of the inflating medium from outside the body to the sack. This device requires two joints, one at each end of the sack. These joints represent potential failure sites, whereby the sack may rupture or separate making the expansion of the sack ineffective and releasing the expansion medium to the bloodstream with increased risk to the individual undergoing the procedure.
Also, indwelling catheters and self-retaining catheters are known that are held in a desired position in a urethra for withdrawal of urine from a bladder. One such catheter is known as the de Pezzer catheter. Such a catheter has a bulbous extremity for holding the catheter in a desired position. Similarly, winged catheters are known that have projections on distal ends of the catheters for retaining them in desired positions.
Further, cannulas, such as Trendelenburg's cannula, are known that have a dilatable rubber bag covering the cannula. Such cannulas are used for closing the trachea to prevent entrance of blood after a tracheotomy.
U.S. patents representative of the aforementioned devices include U.S. Pat. Nos. 2,919,697, 3,834,394, 3,889,685, 3,991,767, 4,130,119, 4,147,169, and Re. 27,910.